Canine parvovirus infection (CPV) has been recently described as a severe, often fatal enteric disease of dogs. We were among the first to recognize and describe this emerging entity. CPV has been seen in and poses a threat to large commercial breeding colonies and closed colonies of research dogs as well as individual companion animals. Although CPV has many clinical and morphologic similarities to feline pauleukopenia (also a parvovirus infection), there is essentially no information available about the pathogenesis of CPV. Because of the growing concern about CPV, we propose here research which will focus on the experimental reproduction of CPV and its subsequent study. We will detail the clinical and clinicopathologic features characteristic of CPV. The effect of route of exposure on incubation period and disease production will be studied. We will define the development and progression of lesions in CPV and their relationship to the distribution of virus. Potentially important variables such as age at exposure and enteric bacterial flora will be investigated. The humoral immune response following infection will be quantitated. Such basic experiments will yield data essential to the setting of future research priorities for CPV and will supply the biomedical research community with information useful in the formulation of initial control measures.